Hmm....Actually, if I were to make a harem anime, it would attempt to be as realistic as possible. No mecha, no mahou shoujo, etc.
As in, a guy, originally monogamous, getting together with many girls(lets say five), all of which are monogamous as well. However, it is not going to be a comedy based romance, but a drama, slice of life, Honey & Clover-esque kind of thing.
The timeline will be from the male chara's last year in high school to his late twenties, after all the girls graduate from grad school and start their careers. It'll be long, so two seasons, like, again, Honey & Clover.
Somehow, the male main chara will eventually be able to bring the group together in some real-life possible manner, say they love him so much they come to a workable agreement of some kind. Maybe during the end of he series, he, in a fit of emo and whimpery, runs out on the women because of his inability to decide between them. The women get together over the weekend and hash it all out, and they decide that maybe living together would work out better for all, especially if earlier in the series, two of the women already teamed up in bed on him before. Then they go out and drag the guy down in public like a pride of lionesses on a antelope.
It might even work out because if all the women pursue their careers, their combined income would be more than enough to provide for all of them and then some, seeing as the only need to pay for one house instead of five. Cooking, cleaning, ect. can be doled out, leaving much more free time than would be possible than in a monogamous relationship. The girls won't turn full on lesbian all of a sudden like you perverts want, but they'll eventually feel experimental enough and comfortable enough to be classified as slightly bisexual.
He won't marry nobody, but in the epilogue, he'll be living with a group of women in one large house a few years after the series end.
He'll have several kids in the house, and each kid has five different mamas to take care of them.
As for specific characters?
The male could be a future author or something, quiet, but intelligent, practical, somewhat guarded emotionally, but sensitive in his own way. Not the center of attention. More of a cat-lover than a dog-guy. Think the guy that likes going out for quiet walks in the park, or the guy that enjoys watching over his friends having fun rather than joining in on them. Contemplative and serene to begin with, but as the series progresses, we can see that he's pretty lonely and wants to change that. Introspective; think Kyon with less sarcasm. Hobbies can be reading books and flying kites(my own hobbies, actually) but enjoys more modern entertainments as well. Physical build? Think slender, not muscled, just a normal, slender guy(like Kyon).
The girls?
Come from all walks of life.
Possible girls, subject to change.
A girl who's parents are divorced, lives with mother who's always out for work. Wants to be a teacher or professor.
Another with a "normal family" that runs a cafe. Wants to open her own cafe in the future.
Two girls, neighbors and best friends, want to become lawyers and have their own law firm in the future. May damage friendship during their fight over the protagonist, but are the two that eventually work together for him first. After all, they are best friends, ne?
A girl whose parents own a clinic, so rich enough and sheltered enough to want to be a social worker or home maker.
A girl who wants to be a doctor or vet, family: "normal."
A "bad" girl(neon highlights, black make up, rowdy) influenced by rock and metal music, wants to be a rock star. Doesn't get along with parents(typical). May have female admirers.
(Another possible two girl combo, one being the rocker, the other being one of her admirers who also likes the protagonist. Imagine:
"Woah! What the hell, *rocker's name*!"
"You're damn lucky, asshole. I don't do this for anyone else, y'know."
"Anno...*male chara*-sempai, I know I am inexperienced, but...um I'llbeinyourcarefromnowon!")
Yeah....thoughts? I really just want something RL possible.